Method of treating soap



July 20, 1937. A. F. TH'A I 2,087,788

METHOD oF TREATING SOAP Filed Aug.- .2;1934` `2 Sheets-.Shed 1 died/f2 Jac/re 1i Y' e y y@www @of 69W zz-Zorn ey@ p f 'A July 20, 1937. A. F. THAI. 2,087,788

METHOD 0F TREATING SOAP Filed Aug. 2, A1954 2 Sheebs--Sheeb 2 fill/1:' 5151/2 Patented July.`2 0, 1937l V.1 l

, Application 1934, sealen, mme y 1 oiaimgiol.' al1-@16) the cost of labor and in ythe consumption of power and heat. .v At the present time the practiceis to pump the upper layer-of nished soap from the soap kettle to a storage tank from which itis drawn as needed for the next operation which comprises first cooling theV soap and then drying the soap.v The o soap is drawn vfrom the storage tankV -intofa mixer, commonly called. av'crutcher and in the crutcher any materials whichcan properly be' added at this stage are mixed with the soap.

soda ash or other alkali fillers. Such fillersare y added only whenva laundry ake soap isdesired and if the soap is to be used for the production oi toilet soap, the additionl of llers inAV the crutcher is omitted and the soap is run directly from the storage tank tofchilling rolls.` o 'Ihe chilling rolls serve. the purpose of solidifying and cooling the hot soapwhich comes either directly from the storage tank orA from the crutcher. The soap is removed from the chilling rolls in the formA of ribbons which arerdropped onto y a conveyer and conveyed to a belt'or tunnel dryer where'a hot air circulation removes vthe desired amount of water; However, lin a belt or tunnel dryer thev drying of the soap is not uniform, the inside of the'fiakes remaining moist and the outside drying excessively and forming a skin, this lskin'eectbeing the formation of avery hard o dry skin on theouter surface of each chip, the interior of thechip'being considerably higher in moisture content. Y

To partially equalize'V the moisture throughout the akes dried inthe belt or tunnel dryer, the

chips are conveyed to a storage bin wherezthey are stored forfa period varying from 12 to 48 hours. During the storage the moisture froml the interior ofeach chip diffuses. toa certain extent .to the hard dry outer skin. and makes the moisture distribution more uniform.

1 After the moisture content'has been'partially equalized inthestorage bins the soap flakes are mixed with perfume and coloring matter. r The coloring matter and perfume are added ina mechanical agitator in which the color and vper- These materials usually consist of sodiumsilicate,

fume is distrlbutedover the exterior of thev chips. In orderfto'distributethel. coloring matter and perfume.v uniformly throughout the flakesr it is necessary to mill the coloredand perfumed chips and for this purposel the chips are run through 5 rd .mlll 1n which they .are ground. .between 'either graniteor4 steel lrollersfwith a result."tl:iat the v coloring matter and v.perilurrie'f vis f dispersed throughout and incorporated in the soap.` A further purpose of milling is to completely climi-.T10y

nate thi? Skin. effect by.3.1`m'r'ul1gf-itlid,L mixing` be; f tween the rollers until a homogeneous product 'is obtained.

After uns ste'ptne soapis'eadyio bepuf inno its fm1 form and .if bar soap is dqsiredhe chips 15 are conveyed to a plodder in'which a packing screwdpresses theflakes intosolidNformw/andfextrudesgthey solidv soap -through: its. outlet" opening. the extruded soap'b'eing subsequentlystamped intobars. f The primary object. of the prsentinvention is to avoid the majority of steps, necessary in' present soaparymg;prossesbyfavoidmethencessity .of cooling the Ysoap beforey being. driedy and by jdryi-ng the soap-inja vacuuml drumsdryer in 25 which thesoapis cooled, fdried land aked without skin efl'ect and can be immediately formed into cakes, thereby' avoiding .the necessity,v of equal-V izing the moisture content i`n itheisoapakes vby storing them in a .bin andsubsequently'milling 30 them. "-1 .s 1 ll'lnother objectV of the y"pl'eseht vvvinvention is to provide,4 in` the production Vlcolofred andpera` fumed soaps, l.,a'.process` in which vv,the.coloririg- 'i matter and perfumecanbe added togthe'soappe-f '35 fore itis driedjand whilestiil liquid.r This nmie nat'es the necessitYOI mixing .the soap chips with coloringmatter andperfumeandthereafter'mille ing the chi .to secure ajuniform distribution of the perfumfandcoloring matter: y 40 Another. objecto'fthe present. ir'iventionjisjto.j`

provide suchffa process for ldrying. Coloringand perfuming soaps in whichfa superior 'soap isfpro'- v `duced inth'at'fthe' soapfhas a. more uniform `and y accurately ,controlled vmoisture Acontent and vfurA 45 therfinthat the coloring 'matterand perfumey is added 'whilefthesoap is liquid a intimately Junitedwiththe ...5081); i i

proviuesucn a .process',w1iic ii yinverter the con- 50 ff' dryer and the outlet from the vacuum"' d1'il.ery 'l' 1 being :directly connectedto plodder where 55 ,d thererforfe'mor l f v bar soap is'desired or being connected with a suitable continuous discharge valve where flake soap is desired.

Another aim of the present invention is to provide such a process in which the soap is dried on small high-speed drums under vacuum thereby permitting large volumes of soap to be dried in a very short time and with very little apparatus.

Another purpose of the present invention is to provide such apparatus whichfwill reduce labor cost and which can be operated with less power and heat'than has been required. in prior vprocesses and in whicha reduced amount 'of floor space is necessary for the equipment.

A further aim of the present invention iszto provide a feeding hopper for the .drying drums which has sealed contact with the drums and permits of employing atmospheric pressure on the liquid soap in the feeding hopper, or any desired vvacuum or pressure thereon without breaking the vacuum in the drying chamber of the vacuum` line 3-3, Fig. `2.

Fig. 4' is a Yfragmentary vertical section Ataken on line 4 4, Fig."2. j Fig. 5 is a fragmentary horizontal 'section taken on line L5, Fig.`l6. Fig. 6 is a fragmentary'vertical enlarged section :taken on line liz- 46, Fig. 3. Fig. 7 isa fragmentary vertical transverse -section, on an enlargedscale, through the scraper blades and one ofthe drying drums. Fig. 8 is a fragmentary side elevation of the scraper'blades taken on 1ine`8.-8,'Fig. 7. Y

Fig .`9 is'avertical Vsection through a continui ousv discharge valve which is substituted at the outlet of the vacuum dryer for thev plodder C when aked soap is desired instead of `bar soap. In accordance with the present invention the liquid soap and the desired amounts of coloring matter and perfume are fed to a crutcher A. The outlet of the crutcher connects directly with the inlet of a'vacuum double drum'dryer -indicated at B, in which, by drying under vacuum,

ythe soap'is dried without skin effect y'andgloss of perfumeto any appreciable extent or deterio-y ration'of colorandfromwhich it is discharged directlyk toa plodder C which presses'the uniformly'dried flakes into solid f orrn and delivers 'the soap from its outlet nozzle after which the delivered soapY can be cut and pressed into cakes. If flaked ysoap is desired the szoapiakes are disgcharged from the Vv acuuin double drum v'dryer f through a continuous discharge valve D'from which thesoap can be vdirectly packaged.;` The crutcherA can' be of `anyfsual form and as 'shown comprises a jacketed]cylindricalY outer shell I5 having a closed bottom and -anopenl top and in which a vertical screw I6 is journalled. This screw worksin -an inner tubular shell Il `which is double walled'and open. at itstopand bottom sc that the screw constantly mOves the material up the center fof `the innersheIl I Il over the top of theinner shell .and down between" the .two shells, therebykeepingthe liquid soap con;-

stantlyin `motion. In' order to keep'the 'soap liquid, steam is supplied tothe-double walled l ner shall I1 and to the jacketed outer shell 5. The screw is turned through suitable gearing I9 arranged at the top of the outer shell I5 and driven by a pulley wheel 20. At the bottom of the outer shell I5 of the crutcher a valve 2| is provided which discharges the liquid soap into the inlet opening 22 of the vacuum double drum dryer B.

The casing of the vacuum double drum dryer is preferablymade of cast iron and consists of a shell 23.which encloseathe drying drums 24 and 25; -`At one end of thecasing 23 ahead 26 is bolted to the casing, this head forming a compartment 2l which is enclosed' by an end cover 28. The opposite end of the casing 23 is closed "by another head 29 which forms a compartment -30 closed by an end cover 3|.

The trunnions 32 and 33 of each drum extend through the end heads 26 and 29 and are suitably journalled in bearings H34 carried by these end heads. The

detailed description is deemed unnecessary.

Ane'ssential element-'of the invention is'the drying ofthesoaponthe heated drumsunder vacuumand for this purpose the casing 23 is" provided vWith a vvapor outlet 39 "which leads 'to any suitable type of eirhausterA (not shown);` 'but preferably of the ycondenser type.

VTo the bottom ofthe casingy 23 is secured a I hopperbottom 40 having adischarge opening 42 which is connected by an adapter 43 vwith the inlet 44 of the plodder C. In order tov lprevent arching of the dried 'material inthe bottom of the hopper 40 Va breaking device is provided which preferably consists of a shaft 45 having a number o'fradial pins 46, this shaft being rotatedv in any suitable manner andbeing jouri nailed4 in bearings finf'tl'ie ends of the hopper bottom 40. f' '.Ihe soapjfrom the valve 2l is discharged through the inlet opening 22 of lthe vacuum dryer into a feed hopper 4 9 which consistsvof side walls `5l! and 5I extending downwardly from 4the top of the-casing 23 parallel with thedrums .24

and 25 and terminating close to the Aupper 'sur.

face ofthe dru'rnsiend walls 52 and 53 which likewise' project downwardly from `the top of the casingj23 immediately adjacent-the Lopposite ends of the drums and are A'joined tothe side walls 59 and '5I; anda top, plate54 which is preferably 4integral with theside and endwalls of the hopper and is preferably bolted tothe top flange Y of the casing'23. The liquid soap is` retained in the .hopper 49 and-'as the drums rotate vthe drurnsurfaces tpick up a layerI or filrny roilrthe liquid soap and dry thesevlayers',\ these layers being subsequently scraped off and 'dropped in sure, or it can be under a partial vacuum. When a partial vacuum isv maintained in the hopper, suitable suction pipes 48 are connected to the upper plate 54 of the feed hopper.

Inasmuch as a vacuum is maintained within the casing 23 and a lesser vacuum or atmospheric pressure maintained in the feed hopper 49, it is apparent that a/seal must be provided-between the bottom of the hopper walls 50, 5|, 52 and 53 andthe drying drums 24 and 25 and forthis purpose adjustable packing means are provided which are preferably constructed as follows:

Each of the-side walls and 5I ofthe hopper is provided on its undersidewith a downwardly facing groove or channel 56 which contains strips of packing 51 surmounted by afollowerbar 58. 'I'his follower bar is pressed downwardly by a plurality of rods 59 which' are spaced'along each of the walls 50 and 5I and extend upwardly through stuffing boxes 60 provided in the cover plate 54 of the feed hopper. In order to adjust the pressure exerted by the rods 59, each of these rodsA is provided' with threads and `is screwed through a bracket 6I secured tothe top or plate 54 of the feed hopper and is squared at its upper end so that by turning the rods they areadjusted vertically. 'I'his adjustment is held bya lock nut 62 on each rod. By adjusting 'the rods 59 up and down any desired pressure is 'applied to the follower bar 58 and the packing 51. This packing provides a reliable seal between the sides of the hopper and the topof the drum surfaces so that the higher pressure on' the liquid soap in the feed hopper'does not force the liquid soap under the side walls of the hopper.

In a similar manner the end walls 52'V and 53 n and cams being provided at suitably spaced in'- tervals so that a uniform pressure can' be exerted on the packing 66, this packing being pressed against the ends of the drums so as to provide a tight seal between the end walls of the feed hopper and the ends of the drums. 'I'he rods 69 extend upwardly through stuffing boxes 10 in the plate 54 of the feed hopper and the upper end o f each of thesel rods is squared as indicated at 1| so that each rod can be conveniently turned. Inv order to hold each rod in its adjusted position the upper end of each rod extends through a bracket 12 and suitable lock nuts 13 are provided between each -rod and the corresponding bracket.

As the drums rotate the'film of soap on the heated drum `is dried under vacuum. 'I'hickness of the lmadhering to the drum surfacemay be regulated by adjustment of the clearance between the two drums, which is accomplished byhaving the bearings 34 of one of the drums movable in a horizontal direction at right angles to the drum axis. After the moisture content has been reduced to the desiredextent the lm on each drum is scraped off by knives or doctor blades indicated generally at 15. Inasmuch as the construction of each of these scrapers is the same a description of one will be deemed to apply to both. Each of the scrapers 15 comprises a knife holder 16 which is journaled in the end heads 26 and 29 of the dryer and a pair of knives 11 and 1ly are removably mounted on each .knifeholder'lin any suitable manner. The knives: 11 `and :18 preferablyeach-have aseries offspaced square projecting cutting portions 19, as best shown in Fig.8, andthese overlap one another so that all the :material is scraped'from the drums. In order to adjust the pressureofthe blades I11.-.and 18 on the drums 4the trunnions `ofeach ofthe knife holders 15 Vand 11 extend through thezend heads 26 and 29 of the dryer and areconnected to levers to the lower ends of which links 8l are pivoted. 'I'he other end of each of these links-8l. is connected -to an adjusting rod 92 whichk extends through astuiiing box 83 in the side wall of the corresponding'compartment-21 or'90. `Each of .l

ythreadedengagernent with its rod for this {purpose. v

Y After the soap is stripped from thedrying drums "it is in condition to bef-nally-packaged either by l. being formed-into cakes orl packedy as chips. If cakes lare beingvprodueed, the soapis discharged into the plodder G.- This'plodder' can be of any-suitable'form and-asfshown comprises this screw'and thisscrew receives and packs the 'soap flakes andl discharges or extrudes the soap a casing 85 vin whicha horizontal packing screw 86 is journaled. vThe inletopening'l 44'fis above 39 Y in the forni of'a solid stream'throu-gha discharge V nozzle 81. The screw 861s turned'1by'means of -a suitable gearing from 'av pulley -89 and the soap dischargedfromf'the nozzle 81 is'cut into suitable lengthsfand pressed 'into bars.

In thev event chips arev desired the outlet -of the adapter 43 can beprovidedwitha continuous discharge valve'D, assh'wn in Fig. 9. Such valves generally consist of.'a cast iron rotor 90 I enclosed in a l'cast iron casing 9| providedA with bearings' and having 'agear drive (not shown), and a vacuum connection 92 for :exhausting each chamber before it enters intocommuni'cation with the-interior of the-dryercasingL In. carrying out my improved process theper- Y fume andcoloring matter is added directly to the hot soap mythe crutcner-A. 'nui-mixes the' perfume and coloring matter with the soap while it is-still hot and fluid and thereby 'secures a very effective dispersal of the `color andA perfume throughout the soap'masswithout thenecessity of milling the soap. Heretoforel ithas'beenv'vho'l-r y ly impracticable to attempt the addition-fof perfume or color at this stage as the* perfume would 1 be either destroyed or driven off by the succeeding usual drying operationand the color, if a soluble aniline color, which is preferredwesliable to'be impaired` or destroyed; By subseqiientlydrying ina vacuum `double drum dryer I amV able add with advantageb'oth the com; and perfume and y such othereleinents as may be desired tothe hot soap in, the crutcher without-fear of destroying on driving on these elements ,during the subsequent drying stage, since kthe cooled while e Y From the crutchen A theghot soap-is discharged into thefeed hopper 49,this feed hopper `being mp1s 'actually sealedtight against both the Y tops and ends of both drums. -.'Ihese drums are rotated inthe direction of thearrows showninlig.- 1 and in I rotating pick upa film-of ythesoap fand carryh it into the-vacuum" chamber` of :the casingv 23,19,

vacuum being Vmaintained in. this chamber throgh the exhaust outlet 39. y

-.-By drying the soap under vacuum it is'unnecessary to cool the soapbefore being dried. as, was necessary heretofore, and thepresent process thereby avoids the waste of heat incident-to first cooling the soap and-then heating it again in the dryer. Further, the tunnel dryerv now generally used for the drying ofvsoap operates at a temperature of about 140 Foto which temperature the soap ribbons from. the chilling mills are exposed for a period of flfteentotwenty minutes. Y Large volumes of air are used in the tunnel dryer which is not only Awasteful of heat and power but also would subject any perfume or coloringmattengif it hadlbeen added before.- hand, to thedanger of oxidation. Further, by

`dryingin a vacuum dryer the chilling of the soap, which was in order to harden the soap before being introduced into the tunnel dryer heretofore, is avoided and this loss of heat eliminated. f The important result, however, of drying un'- der vacuum is the elimination '0L skin effect, the `soap being dried under vacuum rapidly to a 'uniform moisture contentof less than 20%, yas

required by. the trade, therebyavoiding the necessity of subsequently storing or millingthe soap. f By drying under reduced pressure rapid evaporation iseifected because the vapor pressure .of the soap is higheri than `-the pressure vmaintained in the dryer. This evaporation carries oiLheat and causes the soap to coolto a temperature approaching that corresponding to the boiling point of water under-this reduced pressure, as evaporation takes place, thereby cooling and' solidifying the soap without any expense for cooling water and at the same time accomplishing a removal of part of themoisture of the soap. Y,

By using metaldrums a very thin film ofsoap is deposited. on the drums and from this the water vapor can readily escape without any slrir i.eil'ect.- Skin effect is caused by such rapid evaporation from a surface to a layer of wet material that-.the amount of water evaporated from thefsurface is greater than the amountIV of moisture A,which travels from the center of the layer by diffusion. Hereby a skin of dry material is formed on the surface which inhibits or greatly retards further diffusion of moisture from` the' center of the layer. The rate of` diffusionv varies with the thickness and the moisture gradient between center and surface .of the layer. By .revolving the drums at high speed the thickness of the layer is reducedto such an extent that the necessity for revolving at'. high speed diffusion is greatly re.iuced.`v Y

By heating the drums with live steam, heat is transferred through the metal. A small amount of heat so transferred and absorbed by the thin film of soap maintains a temperature at which the vapor pressure of the soap is xnz` .tei'ially higher than the pressure maintainedv in the dryer. As 'a result of the very slight thickness Vofthe illrriv and the resultant ease with which the moisture can travel through the ilm and escape, a rapid evaporation ofthe moisture in the film of soap takes place, the moisture content of the film remains uniform and the temperature of the film cannot rise sufficiently to cause 'it to melt and liquefyagain.. Notwithstandingthefact that the steam used for heating' the-drums is at a higher temperature than the liquid soap fed to the dryer, this soap is cooled and its tempera- ,ameter kand v36v inches in length. This, it will ture .maintained suiiiciently low. to remove it fromthe drum surface in condition for final packaging andrwith sumcient residual moisture tovconform to present commercial standards (540% moisture content). a As a1 result, by drying under vacuum, the soap film dries very quickly. and the drums; can be rotated very rapidly, at a speed from 50` to 150 R, P.- M. and the film-deposited on the drum be very thin. tests indicatingthat the initial thick- 10 ness of the lm should not, exceed '.0015 ofran inch.` This permits the use .of very drums and a vacuum drum dryer `suitable for handling-a thousand pounds per hour `of toilet f soap canlbe made with drums 18 inches in dibe appreciated, greatly economizes in floor space and `the, costof apparatus as compared with the ytunnel `dryer `heretofore necessary, the hot air circulation system for this tunnel dryer, to say nothing ofthe elimination of. the cooling rolls, milling rolls and mixing apparatus incidentto theV prior process.l

Since-theperfume and been added tothe soap before drying andsince the film ofV soap on thedrums dries without skin effect and 4has a uniform moisture content it is immediately available for packaging in its final form. For this purpose the outlet of the vacuum drumdryer isv directly connected tothe plodder C when bar soap is-desired, the soap flakes being pressed into a solid mass by-thepacking screw in this plolder` and extruded through its outlet orifice. 'The soap from theplodder is vstamped into bars. If flake soap is desiredthe outlet of the .vacuum dryer isgequipped with the continu,-v yousY rotary discharge valve shown yin Fig. 9 from which the chips can be directly packaged.

-The .cost of the equipmentfor .operating in accordance with the presentv` invention is, of 0 course, far less than ,the expensive machinery heretofore used andla's an estimate of the saving in operating cost the following comparative figures vare offered. The estimates are lmade on equipment fordrying ,1000 pounds per hour. With 'a tunnel dryer and its accessory equipment of milling rolls, plodder, etc. the following. would be required: y 'j I Floor space.'. f 810 square-feet Power f.. f -65 horse power Steam -460 pounds per hour Cooling water..r ;.--25`gallons per minute Labor $1 80 per hour With a vacuum dryer the followingare required in an actual installation: y

coloring'- matter has ,25

4` From the foregoing it is' apparent that the present invention provides armethodfor drying soap which permits of adding the perfume and coloring matter to the soap whileit is still liquid and thereafter dry the soap and deliver it to a plodder or packaging machine in continuous process.

v Furthermore, the present process eliminates the steps required in prior processes of cooling the soap on a cooling drum; heating for a substantial period o! time in a tunnel dryer; storing the l soap akes to partially equalize the remaining moisture evenly throughout the soap ilakes; mixing of the soap flakes with perfume and coloring matter and milling of the soap for further equalization of moisture and uniform distribution of perfume and color. Further, the cost of the equipment necessary for carrying on the present invention and the cost of operation form or step shown but is to be accorded the full range vof equivalents comprehended by the following claim. K

I claim as my invention:

The methodof treating soap under vacuum-r which consists in withdrawing hot soap in liquid form and at a temperature substantially above the boilingpoint of water under said vacuum and Y having a high percentage of solids directly from a soap kettle, admitting the withdrawn soap ink undiluted form to a vacuum chamber, applying a thin lm of said soap, not exceeding .0015 of an inch, while in said vacuum chamber to a relatively small heated drying drum rotating at'from 50 to 150 R. P. M., thereby to reduce the moisture content and cool the soap, cooling said fllm to a said vacuum and reducing the moisture content of said illm on said drum uniformly-to less than 20% without-skin effect, and scraping the soapv from said surface in substantially solid form in condition to be directly packed in bar or ilake form.

ADOLPH F. THAL.

15 i temperature near the boiling point of water under 

